Method and device for manufacturing pipe-bends, serpentines, and the like



, I n. H. BOHLING.

METHOD AND DEVICE FOR MANUEACJURING PIPE BENDS SERP E NTINES, AND THE LIKE.- 7 APPLICATION nup JULY 16. I911.

Patefiease uzl, 1920.,

' armors nmaomus BonLme,

" uNrrEo STATES "PATIENT OFFICE.

BOHBBOGENWEIBIK or HAMBURG, I G. M. B. 11., or HAMBURG, GERMANY.

GERMANY, ASSIGNOB TO THE FILM METHOD AND DEVICE FOR MANUFACTURING PIPE-BEND S, SERPENTINES, AND

' THE LIKE.

To all wkomit may concern Be it known that I, BunoLr Hmnomus Bo ztnme, citizenof Hambur in the German Empire, residing at amburg, Ger.- many, have invented certain newand useful Improvements in Methods and Devices for Manufacturing Pipe -'Bends, Serpentines,

andthe like, of which the following is a tubes applicable for producing methods however canonly be used to a very limited extent, that; is to say, they are not bends of smallradius of curvature or over they can be only advanta eouslyused, when the pipe is made of sci -'metal, for instance lead or copper. In both instances the material is shrunk or upset on the inner part of the bend and stretched on the outer part. When'the pipe is very sharply bent,'

that is to say, about a very small radius, it will be impossible to avoid the creation of folds and the stretching of the material. on the outer part weakens the wall too much. The said methods are even less applicable, when bends are to be made from pipes hav- -i comparatively thin walls.

he object of thepresent invention is mainly, to produce bends of any .desired radius and any desired diameter of. piping. A particular advantage consists inthe fact that bent pipes having walls of the same. thickness throughout can be produced. In carrying out the method, the pipe is expanded with regard; to diameter and this expansion will account for the surplus material that exists at theinner part of the bend. In using this surplus of material for increasing the diameter of the'. bent pipe at the same time the sur lus material is partly dislodged from its place and distributed Specification of Letters ratent.

projection the pipe for producingbends from pipes with large diameter *and more- 'part b, shaped-similarly to a Patented Sept. 21, 1920.

Application filed July 16, 1917. Serial No. 180.926.

about the pipe side.

According to the present invention it is possible to produce from a thin straight pipe a bend of larger diameter and having' uniform thickness throughout. The distribu-' somewhat toward the outer tion of the material is a consequence of upsetting of the surplus material and at the same time a drawing action taking place transversally. to the axis of the pipe and causing expansion originated by a forward feeding motion. This shrinking or upsetting action is strongest on innermost part of the bend and will decrease gradually toward the outer part.-

the said method, a draw u consisting "of a guiding shaft provided on oneside with a lateral projection or shoulder. By means of this fed over the mandrel will be laterally expanded and-bent toward the surplus of In carrying out mandrel 1s used,

the expanding side, whereby-- .material will be moved from its place to a greater or less extent.

In the drawing the Figures 1 and 2 show two different .forms of construction jot a vention. v Fig. 3 is'an elevation of the mandrel shown in Fig. 2 t urned at right angles and Fig. 4 is a seictionalrelevation of a turther improved mandrel-m connection with a blank pipe curved partly to the form of a bend or serpentine.

In the mandrel shown in Fig. 1 the Y ing shaft a is provided on "-one' end with a one-sided lateral bead b. In the construction shown in Figs. .2 and 3 the mandrel is also provided with a lateral projection, which however horses hoof (b').

Themandrel shown in Fig. 4 has also ashaft (1 is carried by for pulling. the mandrel through the'pipe' 0. Of course either the rod d carrying the" mandrel may be moved and the-pipe 0 held stationa orv the rod d may, be fastened, part andthe pipe 0 may be moved on .forward. The rear end .lportion b of the mandrel has the form of alfrustum o a cone and is -eccentric to the cylindric shaft a, one element 6? of said-'frustum bemandrel used, according to the present 1nhere 'has the shape of 2 91 1106f; The arod d, which is used 33 .next to the element'b 'ment a of the shaft a,

vature is to be thicker ing'acontinuation of the same element a of the cylindrical shaft a, while one element 6 of the frustum extends at an angle to the element a of the shaft (1. In other words this portion 6' is hoof-shaped and if the shaft cated'by" the dotted line circle a, this circle and the periphery b of the end of the portion 6' would be tangent to one another as shown at a". The diameter of the hoof-shaped portion 6' at its end Z 2 corresponds to the inner diameter of the finally bent pipe 7, shown in F ig.' 4 and said portion 6 gradually diminishes in diameter and merges into the cylindrical shaft a. If desired, a partly ringshaped cylinder e may be provided for as a prolongation of the conical part I), having a diameter also corresponding to the inner diameter of the bend and bent itself to. the same curvature as the bend.

Owing-to the element 6 of the part b diverging from the element 6 the material of the forward fed blank will bestretched transversally and thus expanded in diameter, while that part of the pipe, which is of thepart b will be solely drawn against it to contact therewith. The element 6 of the part b will of course profi'er some resistance against the forward feeding of the pipe and consequently an upsetting of the material to be stretched takes place in such manner that the material is partly removed from its place in the progress of diameter increasing, being so distributed that the thickness of the wall of the pipe will be equal throughout. The partly ringshaped prolongation 0 will warrant the exact curvation of the bend and will also serve as a guide for it.

enit is ,desired to produce a spirally shaped serpentine, a draw mandrel is used, in which the element (2 of the conical part b is itself curved corresponding to a spiral line 6 shown in Fig. 4 merging into the elethus the part b" will be turned out from the plane, in which it starts from the shaft (1 and form an oblique prolongation eccentrically to the shaft a.

In producing the bend or in dimensioning the draw mandrel, the radius of curvature and the inner diameter of the straight pipe to be used must be drawn into consideration.

If it is not the aim toobtain an equal thickness of the wall throughout, stance, if the wallon the inner side of curor thinner and therefore in operation the surplus of material is to be used merely to a smaller or even to a greater-extent for expansion, the diameter of the straight pipe will be chosen greater or smaller respectively.

only applicable opp 9 The new mandrel is not were, continued through it, as indi' for inan approximate which but also for pipes of iron or steel in any thickness of the wall and can be carried out cold, if'sufliciently ductile. When heat is applied, the power and the time requisite for the operation will be considerably reduced. The method enables the manufacture of bends of extremely small radius of curvature and large diameter of pipe. It

vdrel adapted to simultaneously bend and expand the material eccentrically to its longitudinal axis.

2. The method of manufacturing pipe bends, serpentines and the like, which consists 1n drawing the pipe over a cylindrical mandrel of the same diameter as the inner diameter of the pipe and over an eccentric projection on the mandrel, whereby the pipe is simultaneously bent and expanded in diameter in a lateral direction only.

- 3. A draw mandrel for use in manufacturing pipe bends, serpentines and the like from a straight pipe or tube, consisting of a cylindrical body, having a projection eccentric to the axis of said cylindrical body at one end and adapted to urge the material of the ipe blank to one side and simultaneously bend the pipe, when the mandrel 1s drawn through the blank.

4. A draw mandrel for use in manufacturing pipe bends, serpentines and the like from a straight pipe or tube, consisting of a cylindricalbody, and a one-sided projection attached to the said cylindrical body at one end and shaped similarly to a horse s hoof, the diameter of which. starting from the cylindrical body gradually increases.

5. A draw .mandrel for use in manufacturing pipe bends, serpentines and the like from a straight pipe or tube, consisting of a cylindrical body, and a one-sided projection attached to the'said cylindricalbody at one end and shaped similarly to a horses hoof, the diameter of which, starting from the eylindrical body gradually increases, an ele: ment of said projection being curved lengthwise to a radius corresponding to that of theinner wall of the outer part of the desired bend.

6. A draw mandrel for use in manufac-' turing pipe bends, serpentines and the like from a straight pipe or tube, consisting of a cylindrical body, a one-"sided projection attached to the said cylindrical body at one end and forming together with said end rustum of a cone, shaped similarly to a horses hoof, the diameter of starting from the cylindrical body gradually increases and being so shaped that the center line is curved in the shape of a spiral.

turing pipe bends,

draw mandrel for use in manufacserpent nes and the like from a straight pipe or tube consisting of a cylindrical body, having a projection eccentric to the axis of said cylindrical body at one end and adapted to urge the material of the pipe blank to one side, when the 10 mandrel is drawn through the blank, and a prolongation at the end of the said body, curved to form the desired bend and of a diameter equal to the diameter of such bend. RUDOLF HIERONYMUS 3611mm. Witnesses: I

F. A. MAX KAEMPFF I. Cmus'r. HAFERMANN. 

